The aza-di-π-methane rearrangement of 1-aryl-4,4-dimethyl-6,6-diphenyl-2-azahexa-2,5-dienes. The influence of substituents on the N-benzyl group

Abstract

The acetophenone-sensitised irradiation of a series of 1-aryl-4,4-dimethyl-6,6-diphenyl-2-azahexa-2,5-dienes has been carried out. All undergo an aza-di-π-methane rearrangement to yield a cyclopropylimine. The determination of the quantum yields for the rearrangement showed a dependence on the nature of the substituents on the N-benzyl group and the reaction is most efficient with electron-withdrawing substituents. The linear relationship between log ϕ and σ⁺ suggests that there is an homoconjugative interaction between the benzyl group and the nitrogen lone-pair.